The present invention relates to a sorter, and more specifically, to a sorter connected to an image forming apparatus, for sorting sheets received therefrom.
Japanese Patent Laying Open Gazette No. 165270/1988 discloses a sorter connected to an image forming apparatus, in which a stapler is provided downward but apart from a sorting unit. After a stack of sheets are sorted by the sorting unit, they are transported to the stapler, where the stapling operation is performed. This apparatus can handle a number of sheet stacks to staple which is greater than the number of bins in the sorting unit.
However, because the stapler is provided under the bins, and since the unit for storing the stapled stacks is disposed under the stapler, it is difficult to remove the stapled stacks from the storing unit.
Japanese Patent Laying Open Gazette No. 231757/1989 discloses a sorter incorporating a stapler. The sorter includes a plurality of vertically movable bins storing stacks of sheets discharged from a copying machine through a sheet inlet. The stapler is disposed at the sheet inlet, and is pivotable between a retracted position, where the movement of bins is not inhibited, and a stapling position where the stapling operation is performed. This mechanism is complicated due to of the mechanism for rotating the stapler.
In order to overcome the problems of both antecedent sorters, the inventors of the present invention have developed a sorter having a stapler which is provided on the copying-machine side of a bin. See U.S. co-pending application Ser. No. 08/053,952. This sorter has an opening on the front side, or operator side, of the sorter through which stapled stacks of sheets are taken out. The sorter can handle a number of sheet stacks which is greater than the number of bins, and it also facilitates the easy removal of stacks of sheets from their bins. Furthermore, the complicated mechanism for rotating the stapler is made unnecessary.
The bins of the sorter are vertically disposed, one above the other and are movable vertically as they are connected to a bin drive mechanism including a pair of rotatable rods, extending vertically, each having a special helical groove on the surface. The copying-machine-side edge of the bins are engaged with these helical grooves, and therefore the bins move up and down in response to the rotation of the vertical rods.
There is a space, or gap, between the bins and the stapler, and the space makes the sorter bulky. The sorter has a pair of hands which nip the stacks of sheets one at a time and transports them-from their respective bins to the stapler. However, the leading edge portion of the stacks can become folded or jammed when the hands push the stacks back from the stapler to their bins.